Foldable rule



July 15: 1958 M..o. AN|-:ERsoN ETAL 2,842,850

FOLDABLE RULE Filed Feb. 5, 1955 .measuring in inaccessible places.

United States Patent() FOLDABLE RULE Martin 0. Anderson and Elmer H. Troselius, Chicago, Ill.

Application February 3, 1955, Serial No. 485,867

11 Claims. (Cl. 33-105) This invention relates to an improvedfoldable rule and more particularly to an improvement in the joint for connecting adjacent sections and to a novel end extension thereof.

Folding rules are extensively used by many tradesmen, particularly those in the building industry. They are usually made of wooden sections co-nnected together with some type of metal hinged joint. During their use, situations arise in which it is highly desirable that a portion of the rule be placed at right angles such as for Also, it is dilricult to accurately measure the inside distance between certain points in such cases where it is impossible to unfold the last section as it would strike some object, thus there is a space between the last section and the final point to be measured which is less than the one section. Hence, it is necessary to make a second measurement. In order to obviate this second measurement an extension is provided at one end which can be extended to complete the distance between the points. The extension is calibrated in such a manner that its value can be readily determined and ad-ded to that of the remaining portion of t-he rule. Where considerable measurements are made throughout the day, this convenience will result in an appreciable savings in time.

Such extensions are not new, as there are a number of rules equipped with this convenience now upon the market. These rules, however, have the disadvantages of not affording a suitable locking means which can be conveniently set and which will not cause excessive wear of the indicia upon the surface of the rule. It is important that the extension be locked in place when used, as there is much less danger of making an error; for if after a measurement is made, there is a slight movement of the extension and it is unnoticed an inaccurate measurement will ensue which may be costly.

An important part of any folding rule is the joint` between each wooden section. A number of types of hinged joints have been introduced for folding rules which are usually based upon the principle of attaching two channel-shaped sheetmetal parts with their web portions connected in back to back relation and their elongated flanges crimped over bevel edges of the adjoining wooden sections. In the prior art, the webs of the channel shaped parts are pivotly attached to each other by a centrally located hollow collar portion extruded from `the web of one member engaging a centrally located aperture within the web of the other with the end of the collar flanged over the web. The web portions are usually embossed to provide some sort of meshing of adjacent parts so an elevated portion of one web meshes between the depressed portionl of the web of the other when the rule is in certain positions. The meshing portions are so designed that they will spring relative to each other topermit the v pivoted parts to be turned when the two members are between the 0 and the 180 positions. At these extreme positions they will again mesh with each other thus ICC holding the rule in a closed or an extended position. To use this spring-like action, resulting only from the elevated portion of one riding on a corresponding portion of the web of the other channel, as the sole means of urging the parts into position is not entirely satisfactory for there is insufficient force to hold the sections of the rule in place when a portion thereof is in a position. In order to prevent the extended portion at right angles to turn as a result of its own weight, it is very important that not only there be a close and ample interlocking of coordinate parts but also that considerable force be exerted to force the parts against each other.

Also, when in an extended position, there is considerable play to the rule especially when it has been used for some time and a firm spring-like action and proper meshing of parts is again needed so that the rule when extended can be lengthened for a considerable distance and held at one end without a joint bending.

It is therefore an object of this invention to disclose a rule with an improved extension locking means.

It is an object of this invention to set forth an improved folding rule which has great resistance to movement at the joint when closed, extended, or when one portion is placed in right angle relationship with the other and still be readily releasable for movement to other positions.

It is an object of this invention to set forth a .novel arrangement of interlocking parts of joints for a folding rule so as to provide maximum resistance to movement during the use of the rule while in an elongated or right angle position but still be readily foldable.

It is a still further object of this invention to set forth a novel type of spring and connecting pin for pivoted joints inl a folding rule which assures continued use with a minimum of deterioration.

It is a still further object of this invention to set forth a novel arrangement of parts in a joint for a rule in which the spring does not interfere with the movement nor the locking of the coordinating parts.

Various other objects will readily occur to those skilled in the art in which this invention is a part.

The preferred embodiments of this invention set forth below for a clear understanding of the essence thereof is best understood by means of drawings in which:

Figure l is a side view of the rule While in a. folded position with several sections unfolded and showing the end extension elongated.

Figure 2 is a top view of a joint when in an unfolded position.

Figure 3 is a side view of the joint shown in Figure 2.

Figure 4 is an exploded view showing the parts of a joint in their respective positions when extended.

Figure 5 is a section through line 5-5 of Figure 2 and lis parallel to the length of the rule at the joint.

Figure 6 is a section through the line 6V-6 of Figure 2 along a line transverse to the length of the rule at the joint. A

Figure 7 is a section through the line 7 7 of Figure l and extends through the locking means for the end extension.

Figure 8 is a section through the line S-8 of Figure 7 and shows the locking spring.

Figure 9 shows the joint in a right angle position.

Figure l0 is a view of Figure 9 looking towards the top end.

In the above-identified figures, 1, 2, 3, are sections of the rule, preferably made of wood and of uniform thickness throughout their length. The adjoining ends of adjacent sections overlap and are connected by aV pivoted joint to form a rule usually six feet in length when extended. 'I'he pivoted joint 4 is made from o e stamped sheet metal which can be of brass or brassplated steel formed into channel-shaped members 6 and 7 with the elongated legs 5 thereof converging for crimping over bevel edges 2S extending in from the over-lapping ends of each section. By tightly crimping the legs of the channel-shaped parts along the beveled edges of each section a firm attachment is effected.

As shown in Figures 1, 2, and 3, the adjacent sections of the rule overlap at the joint and are connected tof gether by the webs S and 9 of the channel-shaped members 6 and 7 contacting each other in back-to-back relation. The parts of the point are assembled before they are attached to the wooden sections which are cut away along their inner faces slightly to accommodate the space required by the joint. The web of each part is embossed in a manner which will be described later, so that they engage each other in interlocking relation. A centrally located pin 10 extends through the center of the web of both parts to form the pivot for the joint. ln order to have the interlocking portion of the web of each joint in firm engagement the spring 11 is placed upon the outside of the web S. The pin also extends through the spring and is riveted upon the outside thereof to form a completed assembly. The spring is in taut position at all times. Thus the adjacent web portions of the adjoining channel members are firmly urged together when in an open, closed, or right-angle position.

In order to have the adjoining sections firmly interlocking while in an extended or folded position, the webs of the adjacent channel parts are embossed adjacent each end into coordinating configurations so that the embossed portion 12 in the member 6 is engaged by a similar shaped portion 13 in the member 7. As mentioned above, these portions are constantly urged into engaging position by the spring 11 which has its terminating elongated ends 14 bearing against and resting in the portions 12 situated at each end of the member 6.

The ends of the elongated portion of the spring are preferably ared slightly upward so that when the joint is turned the ends of the spring will not scrape or dig into the recessed portion into which they rest. There is a slight movement of the spring back and forth across the portions as the adjoining sections are turned.

When the joint is turned, the portion 12 is forced out of meshing with portion 13 and rides upon the web portion of the adjacent channel which further compresses the spring until the parts interlock again at the 0 or 180 positions. This extra compressing of the spring 11 causes the elongated ends to move outwardly hence the desirability of having the ends flared.

Lateral projections 26 are provided on the spring 11 to engage the side inner recesses 15 in the same manner as the ends 14 engage the recesses 12 so as to keep the spring from tipping.

As mentioned earlier, it is also important that a portion of the rule be capable of maintaining a position with* uot moving under its own weight for convenience in measuring at right angles in inaccessible places. This is accomplished by embossing similar inner coordinating recesses 15 and 16 in 90 positions in the web of each member adjacent to and about the pin 10. These recesses are so shaped that they will interlock with each other in any 90 position. Thus these locking portions in the 90 positions are in the shape of a cross with thepin in the center and each portion of the cross having the same contour such as shown in the exploded View of Figure 4. Hence when a part of the rule is moved to any 90'position there are four interlocking portions to provide vgreat resistance to turning.

It is important that all interlocking parts have a fairly close fit so as to rigidly hold the rule in the various positions without much play. As mentioned earlier, the webs should further be embossed in the manner shown inl Figure 4 so that 12 forms a recess on the outside of the web to accommodate the spring thus forming a projection extending inwardly to engage the recess 13 extending outwardly or in the direction of the legs. It is desirable to bevel or slant the edges of all interlocking parts of the adjacent webs of the channels so as to aid in the turning of the rule as they must be forced upon the top of the web for movement. It is necessary to have considerable force on the spring to hold the rule in an elongated or right angle position without turning; any slight bevel to the sides aids in overcoming this when turned. When the spring and parts are properly integrated, they will snap in place in the 0, 90, and positions. It is important to have the spring on the outside for if it were placed between the web portions they could not properly interlock to give the necessary resistance to movement needed for proper utilization of the rule. Without the spring it would not be possible to supply sufficient force to prevent this movement and with a hollow or extruded Divot instead of the pin, there would soon be sufficient loose movement at the joint so that the rule would not function properly after being used for some time.

While the novel combination of the pivot, the spring and the unique interlocking embossed portions of the webs of the joint, particularly adjacent the pin for right angle use of the rule, is an important part of this invention, a further segment of this invention is to provide a novel end extension for the rule. Such an end extension is shown in Figure l. The extension consists of a calibrated milled or extruded metal spline strip 17 .such as from brass, which is capable of being moved back and forth in the slot or rabbeted portion 18 extending inwardly from one end of the rule. The face of the strip is flush with that of the rule. The same indica are engraved on the extension as are placed on the face of the rule. in situations where the rule is only a few inches short of making a complete measurement, the extension can be elongated to complete the measurement thus doing away with a second setting of the rule. The extension is then locked in position by turning the thumb nut 19 which is attached to the exposed end of the bold 20, see Figure 7. The bolt has its head 21 recessed into the lower face of the extension 17. Between the nut 19 and the face of the rule is the fiat spring member 22 having the projections 23 contacting the lower face of the nut so that when it is tightened the spring member 22 is forced against the face of the rule thus locking it in place. When the nut is loosened the spring 22, being slightly bound upwardly, releases itself from contacting the rule thus permitting the extension to be moved. This also does away with wear upon the face of the rule when the extension is moved back and forth as there is nothing contacting it.

The bolt 20 has a rectangular head 21 which engages a rectangular hole within the lower surface of the extension. The elongated head presents the bolt from turning. A shank portion 24 extends through the extension and the spring member. This shank portion is attached to the spring portion 21 by soldering orvflaring of the edges. The remaining portion of the bolt is threaded for engaging the thumb nut with the end upset or ared over so as to prevent the nut from being unscrewed completely from the bolt. Stops may be pro-vided so that the extension cannot be moved beyond the grooved area of the rule. These stops are not shown but can be a pin placed in the bottom of the groove for the inner position and for the extended position the stop may be a small metal plate located across the extreme end of the rule and above the,

face thereof against which the spring member 22 strikes.

By following the invention set forth above, a rule is provided which has a novel pivoted joint possessing great resistance to movement when set in a 0, 90, or 180 position; which will withstand rugged continuous use without deterioration. The rule also provides an improved end extension which can be readily set in any position and moved withoutcausing excessive wear upon the indicia marked'upon the rulesurface.

Having diseidsed a preferred embodiment of this invention so as to enable those skilled in the art of which this invention is a part to practice it, it is not the intent to be limited thereto, but to all such modifications as fall within the true spirit and scope of this invention as set forth by the forthcoming claims.

We claim:

l. In a sectional folding rule, in combination, a springlocking pivoted joint connecting adjoining sections of and yan extension for a terminating end of such rule, said joint comprising a pair of sheet metal channel shaped parts, the webs of said channel shaped parts adjoining in back to back relation and embossed for interlocking engagement, the longitudinal legs of said channel shaped parts extending outwardly and joining together adjacent overlapping sections of such rule when extended, a leaf spring portion engaging the outside surface of the web of one channel shaped part between the legs thereof, and a pin extending through said channel shaped parts and said spring securing said parts together in pivoted relation, said leaf spring comprising elongated ends spaced upon opposite sides of said spring and disposed parallel to said channel and lateral projections upon opposite sides of said pin, the terminating parts of said ends and said projections resting upon said outside surface of said web; said end extension comprising an elongated indicia containing portion slideably engaging a groove extending inwardly from an end of such rule and substantially flush with a surface thereof whereby said extension can be slideably extended beyond said end, a thumb nut, a sprnig-like locking member disposed between the body of the rule and said thumb nut, and a bolt extending through said extension, through said spring-like locking member and into said thumb nut whereby a turn of said thumb nut will lock said spring-like locking member to the surface of such rule and aix said extension in place, the portion of said spring-like locking member extending beyond said extension being slightly bowed upwardly when said thumb nut is loosened whereby there is no wear upon the surface of the end section containing said extension upon movement of said extension.

2. An improved folding rule comprising a series of overlapping sections containing a continuous sequence of measuring indicia upon a common face; a pivoted joint between adjoining overlapping sections comprising .a pair of similar sheet metal channel shaped parts with their webs in back to back relation and embossed for interlocking engagement, the longitudinal legs of said channel shaped parts extending outwardly and engaging adjacent sections, a leaf spring portion engaging the outside surface of the web of one channel shaped part between the legs thereof and a pin extending through said channel shaped parts and said spring securing said parts together in pivoted relation, said leaf spring comprising elongated ends spaced upon opposite sides of said pin and disposed parallel to said channel and lateral projections spaced upon opposite sides of said pin, the terminating parts of said ends and said projections resting upon said outside surface of said web; and an end extension comprising an elongated member engaging a slot extending inwardly from an end of said rule and substantially flush with the indicia containing surface and containing thereon the same indicia as said surface for slideable measurement beyond the end of said rule, a thumb tightening nut spaced above said extension, a spring-like member between said nut and the said indicia containing surface and a bolt extending through the extension, said springlike member and said nut whereby a turn of said" nut forces said spring against said indicia containing surface and locks said extension to the section of said rule forming the end thereof, said spring-like member having a slightly upward bow whereby said spring-like member does not contact the face of said rule when said thumb nut is loosened.

3. In a joint for a sectional folding rule in which adjoining sections overlap at their ends when extended, comprising an assembly of a pair of sheetmetal channel shaped members with their web portions in back to back relation and embossed for interlocking relationship and their leg portions extending outwardly, a curved leaf type spring bearing against the outside surface of one of the said channel shaped members and between the legs thereof and a pin extending through the center of said adjoining channel parts and through said spring placing said spring under tension so that said channel shaped members are urged together at all times, said leaf spring cornprising elongated ends spaced upon opposite sides of said pin and disposed substantially parallel to said channel shaped members and extending a substantial distance therealong and said spring having shorter lateral projections also disposed upon opposite sides of said pin, the terminating parts of said ends and said projections resting upon said outside surface of the said channel shaped members, said assembly placed between the overlapping portions, the leg portions engaging the edges of the section adjacent thereto.

4. A concealed pivoted joint for adjoining elongated sections in overlapping relation when extended, comprising a pair of sheetmetal channel shaped members.

with their webs in back to back relation, embossed portions in said webs for interlocking engagement, the longitudinal legs of said channel shaped members extending outwardly from said webs and engaging the edges of said sections, a leaf spring positioned between the outside surface of one channel shaped member and the inner face of the section engaged at the edges by the legs of the channel shaped member and a rivet extending through the center of said pair of channel shaped members and said spring joining said parts together and placing said spring under tension against the adjacent channel shaped member to urge said interlocking channel shaped member together at all times, said leaf spring comprising elongated ends spaced upon opposite sides of said rivet and disposed parallel to said channel shaped member and extending a substantial distance therealong and said-spring having shorter lateral projections upon opposite sides of said rivet, the terminating parts of said ends and said proiections resting upon said outside surface of an adjacent web.

5. The joint claimed in claim 4 in which a part of said embossed portions mesh and are at right angles to each other about said rivet in symmetrical relationship when portions of said sections are rectilinear or at right angles to each other whereby great resistance to turning at the joints is obtained.

6. The joint claimed in claim 4 in which said embossed portions have a fiat contour and have parts which are symmetrically disposed about said rivet and in which one web is embossed away from the direction of the legs of the same channel shaped member and the other web portion towards the leg of its channel shaped member to provide a configuration whereby a tight interlocking of the adjoining parts are accomplished when said sections are in extended or right angular relation,

7. The joint claimed in claim 6 in which the terminating parts of said leaf spring rest in the recess formed by the embossing of said first named web.

8. A concealed pivoted joint for adjoining elongated sections in overlapping relation, comprising a pair of sheetmetal channel shaped members with their webs in back to back relation, embossed portions in each of said webs for interlocking engagement, the longitudinal legs of each of said channel shaped members extending outwardly from its web and engaging the edges of an adjacent section, a leaf spring positioned between the inner surface of the channel shaped member embossed away from an adjacent section engaged by the legs of the said channel shaped member and a pin extending through the center of the web of both channel shaped members and said spring joining them together and placing said spring under tension to urge said channel shaped members together, a part of said embossed portions being at right angles to each other about said pin to provide a intermeshed symmetrical relationship when portions of said sections are rectilinear or at right angle to each other whereby resistance to turning at the joints are greatly increased, said leaf spring comprising oppositely spaced elongated ends parallel to and extending a substantial distance along said channel shaped members and shorter lateral oppositely spaced projections extending from but adjacent to said pin, all the terminating portions of said spring resting upon the inner surface of a channel shaped member.

9. A folding rule having an end extension comprising a graduated rule having a rabbeted slot extending inwardly from an end of Said rule upon a face thereof, an elongated member slideably engaging said slot and substantially ush with the face of said rule and containing indicia on its surface similar to that of said rule, and locking means for aixing said elongated member in a predetermined position, said means comprising a bolt extending transversely through said extension with a projection above said face, a thumb nut attached to said projection and a spring member between said nut and said face whereby a turn of said nut forces said spring against the face of said rule, the portion or" said spring member extending beyond said elongated member spaced from the face of said rule when saidthumb nut is loosened.

10. A folding rule having an end extension comprising a rule having a rabbeted slot extending along a face and inwardly from an end of said rule and having recessed side walls, an elongated member slideably engaging said slot and substantially flush with the face of said rule and containing the same measuring indicia thereon as on the said rule, and locking means for afxing said elongated member in a predetermined position, said means comprising a thumb nut spaced above said elongated member, a bolt extending at right angles through said elongated member and securing said thumb nut to said elongated member and a fiat spring-like member positioned between thetace of said rule and said thumb nut whereby tightening said thumb nut causes said spring to bear against the face of said rule thereby locking said extension in place, said spring-like member having a slightly upward bow whereby said spring-like member does not Contact the face of said rule when said thumb nut is loosened.

11. The folding rule claimed in claim 10 with means to prevent said bolt from rotating when said thumb nut is turned.

References Cited in the tile of this patent UNITED STATES PATENTS 669,766 Rieker Mar. 12, 1901 884,255 Zweigler Apr. 7, 1908 1,309,930 Akin July 15, 1909 1,226,172 Benjamin May 15, 1917 1,226,173 Benjamin May 15, 1917 1,227,206 Schade May 22, 1917 1,248,174 Schwartzman Nov. 27, 1917 1,488,482 Eckman Apr. 1, 1924 1,512,728 Watson Oct. 21, 1924 1,983,651 Anderson et al- Dec. 11, 1934 1,998,018 Kadu Apr. 16, 1935 2,021,202 Sauer Nov. 19, 1935 2,655,730 Proctor Oct. 30, 1953 2,633,641 Fleming Apr. 7, 1953 2,723,458 Helin Nov. 15, 1955 FOREIGN PATENTS 56,718 Germany May 19, 1891 KARL H., AXLINE UNITED STATES PATENT OFFICE CERTIFICATE 0E CORRECTION Patent NLM, 2,842,850 July l5, 1958 Martin O, Anderson et al.

It is hereby certified that error appears in the printed specification of the above numbered patent .requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line l2, for "point" read joint un; line 57, for "not" read out column 4, line 39, for bold" read bolt m; line if?, for "bound" read bowed line 54, for "presents" read mprevents wg column o, line 39, for "member" read members --T Signed and sealed this 19th day of January 196()o SEAL) ttest:

ROBERT C. WATSON Attesting Oicer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent- NO., 2,842,850

Martin Oa Anderson et al.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line l2, for "point read joint @-5 line 57, for "not" read out column 4, line 39, -for Hbold read bolt m; line 4'?, for "bound" read bowed line 5A, for "presents" read -nprevents wg column o, line 39, for "member" read members Signed and sealed this 19th day of January 1960,

KARL H.. AXLINE Attesting Officer ROBERT C. WATSON Commissioner of Patents 

